Northern Illinois is due to regress, but it still has running back Cameron Stingily (42) carrying the football. / David Butler II, USA TODAY Sports

by Paul Myerberg, USA TODAY Sports

by Paul Myerberg, USA TODAY Sports

Things are getting complicated atop the Football Bowl Subdivision. What was once a foregone conclusion â?? that the Southeastern Conference ruled the roost â?? has become a two-horse race, thanks to the Pac-12 Conference's rapid growth since adding Utah and Colorado for the 2011 season.

The Pac-12 has made its case with numbers unmatched even by the SEC. The latter still leads when it comes to title contenders; Alabama, Auburn, LSU and the rest remain tough to overlook. Where the Pac-12 leads is in wall-to-wall depth, beginning with Oregon and Stanford, rolling through UCLA and USC, and continuing with Washington, Arizona State and the rest.

So any FBS conference rankings begin with one or the other, and you can't go wrong either way. What's equally interesting to consider is where the major conferences rank after the top pair: Florida State's part of the ACC, the Big Ten is promising and the Big 12 has Oklahoma and Baylor â?? so it's complicated.

With media days set to commence across the FBS, here's a midsummer glance at where the conferences rank. At least the bottom part is easy: Conference USA, the Mid-American Conference and the Sun Belt conference bring up the rear.

1. SEC

Top four: Alabama, Auburn, LSU, South Carolina

In terms of pure wattage, no league can match the SEC's top half: Alabama, Auburn, LSU and South Carolina lead, followed closely by Georgia and a sixth national contender â?? whether you want to say Texas A&M, Mississippi, Missouri or Florida â?? in creating the deepest cast of potential playoff participants. Where the SEC lags is in its bottom third, where the decline from the elite top slice is severe. Hey, someone has to lose.

2. Pac-12

Top four: Oregon, Stanford, UCLA, USC

The deepest league in college football has drawn within a whisker of the SEC as a result of huge gains in the South Division. We knew Oregon and Stanford would lead the charge; USC, UCLA and Arizona State have joined the party, however, giving the Pac-12 as many as nine teams capable of winning nine or more games during the regular season. All told, don't be surprised if 10 teams â?? all but California and Colorado â?? end up with seven wins. In a very short period of time, the Pac-12 has closed the gap.

3. ACC

Top four: Clemson, Duke, Florida State, Louisville

Any league headlined by Florida State earns our respect. But the Seminoles' dominance has contributed to the idea â?? largely unfounded â?? that the ACC lacks depth. In truth, FSU merely outshines a fairly competitive conference: Clemson's superb, Duke is on the rise, Louisville adds punch and as many as five teams could conceivably take home the Coastal Division. The league still needs UNC and Miami (Fla.) to deliver, but the ACC is on the rise.

4. Big Ten

Top four: Michigan State, Nebraska, Ohio State, Michigan

Urban Meyer's arrival has added some juice to the Big Ten, as has James Franklin's leap from the SEC to Penn State. What the Big Ten needs â?? and this is an annual refrain â?? is a second national contender to join the Buckeyes, with Michigan State pulling the honors a season ago. The Spartans aren't going anywhere in 2014 despite some losses; can Nebraska, Wisconsin and Michigan join the party? If so, the Big Ten is going to leap past the ACC as the nation's third-best league. Even if not, the league is solidly in fourth. There is, as always, a good amount of potential.

5. Big 12

Top four: Baylor, Kansas State, Oklahoma, TCU

The Big 12 has an issue: it may be too deep. That seven of the league's 10 teams would be wildly disappointed with a finish outside the postseason â?? and an eighth, West Virginia, would be simply angry with another losing season â?? essentially prevents one single team from escaping the regular season unscathed, perhaps costing the Big 12 a spot in the College Football Playoff. In terms of depth, however, this is a very solid league â?? and it'll improve its standing if Texas can rediscover its groove under Charlie Strong.

6. American

Top four: Cincinnati, East Carolina, Houston, UCF

The American does lose Louisville and Rutgers â?? well, loses Louisville â?? but adds East Carolina, Tulsa and Tulane â?? well, adds ECU. The top four isn't terrible: UCF will be a 10-win threat, Houston is underrated, Cincinnati is always a threat and ECU should hit the ground running from the start. The American's issue lies in the mess beyond the top quartet, a group that may include just one eventual bowl team. Is Tulsa ready to rebound? Can Tulane maintain its current growth against a higher caliber of competition? The league gets ugly after the leaders.

7. Mountain West

Top four: Boise State, Fresno State, San Diego State, Utah State

The Mountain West is nipping at the American's heels. Boise State is Boise State. Fresno State reloads without its star skill players but with Tim DeRuyter. Utah State is supremely dangerous despite one of the lowest numbers of returning starters in the country. San Diego State is on an eight-win roll. What could lift the conference above the American is six-plus wins from the group of San Jose State, Nevada, Colorado State and UNLV; if so, this is the sixth-best conference in the FBS.

8. Mid-American

Top four: Ball State, Bowling Green, Northern Illinois, Toledo

Northern Illinois' projected decline â?? it'll be slight, but the Huskies will drop a touch â?? robs the MAC of a potential top-20 finisher. At the same time, perhaps Toledo finally breaks through, ending a frustrating run behind NIU, or perhaps Bowling Green grasps Dino Babers' style to notch another double-digit-win season. Ball State will also struggle matching last year's 10-win finish, but Buffalo, Akron, Central Michigan and Ohio should at least flirt with the postseason.

9. Conference USA

Top four: Marshall, North Texas, Rice, UTSA

Conference USA does house the non-major team with the best shot at an undefeated season: Marshall has the talent, experience and schedule to make a run at 13 wins. But the well quickly runs dry after the Thundering Herd, UTSA, Rice and North Texas; Conference USA's bottom third is as bad as it gets, so the pressure is on Doc Holliday's gang to do all of the heavy lifting. Well, at least most of it: UTSA could be one of the great surprises in the country. The league as a whole is still one of the nation's weakest.

10. Sun Belt

Top four: Arkansas State, Louisiana-Lafayette, South Alabama, Troy

The Sun Belt brings up the rear â?? again. Arkansas State's always steady. South Alabama is growing rapidly. Troy is ready to rebound. UL Lafayette is eyeballing 10-plus wins. Yet this same league also houses five of the nation's worst: Georgia State, Georgia Southern, New Mexico State, Idaho and Appalachian State. In total, six Sun Belt teams were either in the Football Championship Subdivision or participating as an independent within the past three seasons.